March 2015: Refactored/cleaned up the code, added "history" to show all the arrows computed in the process.

November 2015: More refactoring, fixed a bunch of bugs (including a silly indexing issue),
added support for a configuration. See this config file for an example or below
(must be placed in the same dir of the applet).

Since java applets have become a sort of security liability in the last few years, you
might have troubles running the applet. If you have java installed, you can
download the runnable version and just double
click it to run it.